This invention relates to plant growth accelerating and plant root aeration devices, more particularly to mechanical and air root pruners which are adapted to be implanted within plant medium to accelerate and enhance the development and growth rates of root balls and subsequent vegetative growth of plants grown therein, to combinations of an implantable aerating root pruner (hereinafter called xe2x80x9cIARPxe2x80x9d) and a root cutting implement (hereinafter called xe2x80x9cCUTTERxe2x80x9d) for cutting roots growing into the IARP, and to an IARP insertion/cutting implement (hereinafter called xe2x80x9cINSERTERxe2x80x9d) that can both cut roots growing into the IARP as well as facilitating the penetration and placement of the IARP into soil or plant media while minimizing the work required to do so.
Air root pruning devices and methods are well known in the prior art. See, e.g., U.S. Pat. Nos. 4,442,628; 4,497,132; 4,510,712; 4,574,522; 4,716,680; 4,753,037; 5,222,326; 5,301,465; 5,557,886 and 5,761,848. In each of these devices the air root pruning structure and function is an integral element of the container in which the plant is to be grown, thereby contributing significantly to the cost of its production. U.S. Pat. No. 5,241,784 discloses a slotted air root pruning plant root container that is inserted into a plant pot. None of these prior art air root pruning devices has achieved continuing commercial success, for a variety of reasons which include the need for the use of customized pots and one or more of difficulty in removing the mature plant from the plant pot; higher production cost of such customized plant pots; loss of planting medium from the plant pots; increased shipping costs because of their lack of stackability; and incompatibility with automatic equipment used by commercial growers for filling plant pots with planting medium.
U.S. Pat. No. 4,175,356 discloses a plant aerator tube with radial perforations in it whose purpose is to reduce the undesirable effects upon the health of the plant of top watering and over watering. Structurally, the aerating tube of the ""356 patent lacks a significant air root pruning effect because only a very limited number of roots of a plant growing in a pot in which it is inserted would be affected in an air root pruning way by its presence in the pot.
U.S. Pat. No. 4,682,550 discloses an apparatus for loosening, aerating and fertilizing soil plant roots intended for temporary insertion into a predrilled hole in soil for injecting fertilizer, high pressure air and water into the soil. U.S. Pat. No. 3,962,822 discloses a slotted physically or biologically degradable plant container adapted to block growth of roots through the slots thereof when a plurality thereof are positioned side-by-side and to permit growth there through when the containers are separately imbedded in the ground.
In our prior issued U.S. Pat. Nos. 5,782,035 and 5,918,415 we disclose an air root pruner adapted to be fitted in an automatic watering garden container. The IARP device of this invention differs inter alia from the air root pruners of the prior art by being useable in any planting medium regardless of its location be it ground soil or planting medium contained within a plant pot or other container. They are easily inserted by hand into loosely packed soil, such as common potting soil, and can also be implanted into more densely packed soils using the combination of the IARP and its companion inserter/root cutter device of this invention. The IARP can be inserted into planting medium in a plant pot, either before or after the pot contains a growing plant, or into soil proximate a plant growing in the ground. The IARP has a dramatic effect upon the rate of root ball and vegetative growth of a plant growing proximate thereto. It differs structurally from the perforated stakes of U.S. Pat. No. 3,962,822, inter alia, by providing a much larger number of perforations in the portion of the wall thereof which faces the plant, thereby achieving an enhanced aeration of the root ball and additionally providing a passive air root pruning effect as well as enabling mechanical pruning of roots with the IARP cutter or the cutter implements.
The method of this invention provides an economical way of increasing the rate of fine hair and lateral root development and thus the vegetative growth rate of a plant using inexpensive and reusable devices.
It is an object of this invention to provide an aerating root pruner which lacks most or all of the deficiencies of the above-described prior art aerating and air root pruning devices. It is another object to provide an aerating root pruner in the form of a perforated conduit whose perforations provide the conduit with a high ratio of total open area to total surface area. It is yet another object to provide an aerating root pruner whose geometry and strength facilitates its insertion into hard packed planting medium. It is a further object to provide an aerating root pruner, which provides a high level of ambient air access to the planting medium along the length of the conduit when inserted therein. A further object is to provide a device which promotes uniform distribution of water in the planting medium from its surface to the bottom of the pruning stake and which has an air root pruning effect on the roots of a plant growing proximate thereto in the planting medium.. A still further object is to provide a method of accelerating the rate of growth of a plant by growing the plant, either in a plant pot containing one or more of the IARP""s of this invention in the planting medium on in ground containing one or more of them proximate to the growing plant. Other objects will be apparent to those skilled in the art to which this invention pertains.
In a first article of manufacture aspect, this invention relates to an implantable aerating root pruner (IARP) comprising a pair of thin walled substantially rigid sheet members dismountably fitted together in a spaced apart configuration which forms a stake-like conduit, at least one of which sheet members have a plurality of apertures therein which form a grate-like structure which provides the conduit with a high ratio of total open area to total surface area, a first end of each of which sheet members is tapered to form, when the sheet members are fitted together to form the first article, an edge or point to facilitate insertion of the first article into planting medium and the end portion of the other end of each sheet members lacks the apertures and is adapted to project above the surface of the planting medium, which conduit provides ambient air access to the planting medium along the length of the conduit when the first article is inserted in the planting medium and thereby promotes enhanced aeration of and uniform distribution of water in the planting medium from the surface of the planting medium to the bottom of the pruning stake and which has air root pruning effect on the roots of a plant growing proximate thereof in the planting medium.
In a preferred aspect of the first article of manufacture aspect, both sheet members are separate, apertured, flat walled and fit together to form a thin elongate rectangular box-like structure whose front and back faces are formed by the sheet members and comprise joining means which render the sheet members readily joinable together and separable from each other. In a more preferred aspect, the sheet members are identical. In other preferred aspects, the first article of manufacture is one or more of formed of injection-molded polypropylene; and the ratio of the total apertured area to total solid area is at least 2:1.
In an alternative aspect of the first article of manufacture aspect, the sheet members are semi-cylindrical and permanently joined together along one side edge thereof in a side-by-side position by flexible hinge-like connecting means which permits the sheet members to be folder together to form a cylindrical conduit and the sheet members are held in their conduit configuration along the respective other side edge of each thereof by disengageable latch means which permits the sheet members to be reopened to their side-by-side position.
In a second article of manufacture aspect, this invention relates to a combination of the first article of manufacture as defined hereinabove or any of its preferred aspects thereof and an elongate rectangular thin-walled grate-like apertured substantially rigid root cutter plate adapted to be slideably and removably inserted into the first article, in sliding contact with the inner face of one of the apertured sheet members of thereof, to a first position in which its leading end is proximate the bottom of the first article, its other end thereof projects outside the first article and its apertures are out of registry with the apertures of the sheet member with which the cutter plate is sliding contact when the cutter and adapted to be further inserted to a second position in the first article in which its leading end is in contact with the inner leading edge of end portion of the sheet member and its apertures are in registry with the those in the sheet member, and thereby mechanically sever any roots which have invaded the space between the cutter plate and the inner wall of the other sheet member.
In a preferred aspect of the first combination aspect of this invention, the cutter plate has a canopy on its second end which covers the air space between the upper ends of the two sheet members which form the first article of manufacture, thereby preventing planting medium or debris or trash from entering that space while a plant is growing in the plant pot without blocking movement of ambient air within the first article. In other preferred aspects, the first article of manufacture has one or more of the other preferred aspects thereof described hereinabove.
In a first method of use aspect, this invention relates to a method of using the first article of manufacture aspect of this invention to promote the growth rate of a plant by air root pruning the roots thereof, which comprises the step of inserting the first article of manufacture, as defined broadly hereinabove or a preferred embodiment thereof, in the plant medium either before the plant is planted therein or thereafter before the root ball of the plant has fully formed, close enough to the growing plant to be contacted by the tips of the growing roots of the plant; and maintaining the first article in the planting medium for a period of time until in roots of the growing plant have invaded the interior of the first article.
In a preferred aspect, the first method of use comprising the further steps of (a) inserting the first article of manufacture into the planting medium with a handled insertion tool slideably and removably into the interior of the first article until the leading end is at least substantially completely inserted therein, before the first article of manufacture is positioned in the planting to assist the insertion of the first article therein, and/or thereafter when the roots of the plant have invaded the interior of the first article to mechanically sever the roots which have invaded the interior of the first article; and (b) thereafter withdrawing the insertion tool from the first article.
In a second method of use aspect, this invention relates to the use of the first combination of this invention to promote the growth rate of a plant by air root pruning the roots thereof, which comprises the steps of inserting the first combination of this invention as defined hereinabove in the plant medium either before the plant is planted therein or thereafter before the root ball of the plant has fully formed, close enough to the growing plant to be contacted by the tips of the growing roots of the plant; and maintaining the first article in the planting medium for a period of time until in roots of the growing plant have invaded the interior of the first article.
In a preferred aspect, the second method of use aspect comprises the further steps of (a) slideably and removably inserting an insertion tool into the interior of the first article of manufacture of this invention until the leading end is at least substantially completely inserted therein, before the first article is inserted in the planting medium, to assist the insertion of the first article therein, and/or thereafter when the roots of the plant have invaded the interior of the first article, to mechanically sever the roots which have invaded the interior of the first article; and (b) thereafter withdrawing the insertion tool from the first article.
In a third of method of use aspect, this invention relates to a method of using the first combination of this invention as defined broadly hereinabove or a preferred embodiment thereof promote the growth rate of a plant by both mechanically and air root pruning the roots thereof, which comprises the successive steps of (a) inserting the combination into the planting medium, either before the plant is planted therein or thereafter before the root ball of the plant has fully formed, close enough to the growing plant to be contacted by the tips of the growing roots of the plant; (b) maintaining the first combination in the plant medium, with the cutter plate positioned in the first article of manufacture as defined hereinabove so that their respective apertures are in registry, for a period of time until roots in the growing plant have invaded the interior of the first article; and (c) thereafter moving the cutter plate from the first position in the first article to a second position in which their respective apertures of the sheet members and the cutter plate are out of registry, thereby mechanically severing the roots which have invaded the interior of the first article.